Summary: Transformation Groups, Vol. ?, No. ?, ??, pp. 1­?? c Birkh¨auser Boston (??)
A DEODHAR-TYPE STRATIFICATION
ON THE DOUBLE FLAG VARIETY
BEN WEBSTER
Department of Mathematics
University of California
Berkeley, CA 94720
MILEN YAKIMOV
Department of Mathematics
University of California
Santa Barbara, CA 93106
Abstract. We describe a partition of the double flag variety G/B+
× G/B-
of a complex
semisimple algebraic group G analogous to the Deodhar partition on the flag variety G/B+
.
This partition is a refinement of the stratification into orbits both for B+
× B-
and for the
diagonal action of G, just as Deodhar's partition refines the orbits of B+